How to Use a SIP Calculator to Plan Your Mutual
A practical guide on using a SIP calculator — inputs explained, CAGR assumptions, step-up SIP planning, and how to reverse-engineer your target corpus.
A SIP (Systematic Investment Plan) calculator helps you answer two types of questions: (1) How much will my monthly investment grow to? and (2) How much do I need to invest monthly to reach a target corpus? Here is a practical guide to using one effectively.
SIP Calculator Inputs Explained
- Monthly Investment: The fixed amount you invest each month (e.g., ₹5,000).
- Expected Return Rate: The assumed annual return (CAGR). Use 10–12% for large-cap equity funds, 12–15% for mid/small-cap, and 6–7% for debt funds.
- Investment Tenure: Duration in years (SIPs work best over 7+ years).
SIP Formula
FV = P × ((1 + r)^n − 1) / r × (1 + r)Where FV = future value, P = monthly SIP amount, r = monthly rate (annual ÷ 12 ÷ 100), n = number of months.
Example: Planning for ₹1 Crore Retirement
Goal: ₹1 crore in 20 years. Assumed return: 12% per annum.
Working backwards: you need to invest approximately ₹9,500 per month to reach ₹1 crore in 20 years at 12% CAGR.
If you can only invest ₹5,000/month, extend the tenure to ~26 years, or combine SIP with a lump-sum investment.
Step-Up SIP: The Power of Annual Increases
A step-up SIP increases your contribution by a fixed % each year (usually matching your salary increment). Starting at ₹5,000/month and increasing 10% annually:
- Standard SIP (₹5,000 flat, 12%, 20 years): ≈ ₹49.9 lakhs
- Step-up SIP (10% annual increase): ≈ ₹1.04 crore
A 10% step-up doubles your final corpus with the same starting amount.
Realistic CAGR Assumptions by Fund Type (India, 10-year average)
| Fund Category | 10-Year CAGR |
|---|---|
| Large-cap equity | 10–12% |
| Mid-cap equity | 13–16% |
| Small-cap equity | 15–18% (high volatility) |
| Balanced/Hybrid | 9–11% |
| Debt/Liquid | 6–7% |
Common Mistakes to Avoid
- Using unrealistic return assumptions — 20%+ CAGR is not sustainable for planning purposes.
- Not accounting for inflation — ₹1 crore in 2046 is worth much less than ₹1 crore today.
- Stopping SIP during market downturns — dips are when rupee cost averaging works best.
- Not reviewing fund performance — reassess annually and switch underperforming funds.
Try our SIP Calculator to model your investment plan with step-up options.